MARBLEHEAD - Two years ago, lymphoma survivor Nina Savignano was working at a credit union when the numbers on her computer screen started to blur. Thinking she needed a quick trip for new glasses, the 24-year-old discovered instead that she was about to begin a nightmarish medical journey.

The cancer had returned, spreading to Savignano's brain and nervous system and requiring aggressive treatments that left her temporarily unable to walk or speak. The six-month fight wiped out her family's finances, leaving Savignano confined to a MassHealth-supported nursing home and forcing her infant daughter and her mother toward homelessness.

But as they were on the brink, Savignano and her family were awarded a subsidy from the state to pay for a safe and airy Marblehead apartment, in a first-floor setting conducive to rehabilitation. "They saved my family," her mother, Yvette Barr, said of the state program.

Now that $33 million program could be slashed, potentially knocking Barr, Savignano, and thousands of others - many of them elderly, disabled, or families with young children - back toward homelessness.

With state revenues plummeting, House leaders proposed a budget Wednesday that would substantially cut the Massachusetts Rental Voucher Program, meaning that nearly half of the 5,171 households that receive these subsidies could lose them.

"We cut a lot of good programs," said Representative Charles A. Murphy, chairman of the House Ways and Means Committee. "Tough decisions had to be made."

The $27.4 billion House budget proposal calls for the steepest spending reductions in memory, including several to programs serving the state's most vulnerable residents. Top lawmakers said they had little choice, facing an estimated deficit of $3.6 billion. Much of the budget could not be cut, contractual obligations such as employee healthcare and retiree pensions, so that left decisions about which of the remaining lines to eliminate.

Among others, the House budget would delete a $3.5 million jobs program for at-risk teenagers and wipe out $13 million in grants to counter gang violence. It would reduce subsidies to the state's food banks from $12 million to $8 million, at a time when pantries and shelters have seen need grow 10 percent or more over the previous year.

The governor's budget, in contrast, contained more funding for these programs, as well as new revenues, proposing sales taxes on alcohol and candy and tax increases for meals and hotel rooms. Murphy and Speaker Robert A. DeLeo have avoided talk of tax hikes amid a recession.

"Every time there's a problem, you just can't tack on a tax," said Murphy, a Burlington Democrat.

As lawmakers debate the budget, advocates for lower-income residents hope they restore funding to a variety of programs before approving the final 2010 budget, which takes effect July 1.

"The impact is substantial," said Catherine D'Amato, president and chief executive of the Greater Boston Food Bank, which handles the current $12 million state contract to buy the nutrient-rich staples that supplement private donations at roughly 800 pantries, soup kitchens, and shelters across the state.

"We fully embrace that our state is in a financial crisis; this is true across America," D'Amato added. "We also hope that this state and the decision makers will embrace the fact that there's a safety line here."

For Barr, Savignano, and 4-year-old Aliviah Savignano, that safety line is the rental voucher that pays 90 percent of the $1,664 monthly rent on a three-bedroom, one-bath apartment they could not otherwise afford.

When Savignano's cancer came back in life-threatening fashion, Barr quit her job as a dispatcher for a security firm to care for her daughter. Barr had already lost her car and was on the brink of losing her two-bedroom Lynn apartment, while her daughter underwent slow rehabilitation at a nursing home, paid for by MassHealth, when the family landed a subsidy through the Massachusetts Rental Voucher Program in late 2007.

Governor Deval Patrick's fiscal 2010 budget proposed increasing the state program slightly, from its current $33 million to nearly $36 million. The House proposal instead slashed it to less than $18 million.

"People who have been depending on the subsidies to keep a roof over their head are now going to have that pulled out from under them," said Leslie Lawrence, associate director of the Massachusetts Coalition for the Homeless.

Affordable-housing advocates say the cut would cost taxpayers more in the long run, as evicted residents turn to the shelters of the state Department of Transitional Assistance. The rental subsidies provide an average of $560 a month to recipients; the state's emergency shelters cost about $3,000 per family per month to operate.

"Even if only half the families end up in a shelter . . . that's $41 million in [new] shelter costs," said Chris Norris, executive director of the Metropolitan Boston Housing Partnership.

It would also destabilize families and fly "in the face of the commitment to end homelessness," added Norris, whose nonprofit agency administers the vouchers in the Boston area and placed Barr's family in Marblehead.

In an interview at the apartment yesterday, an emotional Barr, now 47, said she wakes up every morning thanking God and thanking the housing partnership. "I call it a miracle," she said.

The voucher has provided otherwise unimaginable stability amid chaos, Barr said, holding her daughter's hand and sitting near photos of her granddaughter, who was off at preschool. One showed Aliviah dressed as Disney's Ariel, marking her third birthday in 2007 with a small party at her mother's nursing home, when the family's situation was more precarious.

"With this voucher, my daughter [now] lives in Marblehead, in a beautiful three-bedroom apartment, where she can walk, exercise, go to the ocean, peacefully rehabilitate," Barr said, letting out a small sigh. "My granddaughter goes to school a two-minute walk from the house. And I'm able to breathe again."